This project was initiated to evaluate the family members of African Americans with End Stage Renal Disease associated only with hypertension in order to understand why African Americans have a higher incidence of kidney failure. In this group of patients, the cause of the hypertension and renal disease is unclear. We suspected that the first-degree relatives would be at an increased risk of developing renal failure. We first surveyed 147 first-degree relatives with baseline screening tests for hypertension and renal function. Now we are investigating those first-degree family members with normal or only minimal renal dysfunction through the GCRC. We are measuring the renal function (glomerular filtration rate and renal blood flow), insulin/glucose response to an oral glucose load, blood pressure responses to salt loading and depletion, renin/aldosterone responses, and the pattern of salt excretion after salt loading. We have established two control groups of age/gender matched African Americans. one group has hypertension but no family history of renal disease. The second group has normal blood pressure and no family history of hypertension or renal disease. We have conducted 56 outpatient GCRC investigations, 48 during this reporting date and 43 inpatient GCRC 3 day protocols of which 41 were during this reporting date.